In some networks, the packaged data is classified into different Quality of Service (QoS) classes that dictate how competing traffic flows are provided resources. Such resource allocation affects how quickly the packaged data travels from a source to a destination. For example, a distinction may be drawn between packets carrying video data (i.e., video packets belonging to a video QoS class) and packets carrying general data (i.e., general data packets belonging to a general data QoS class such as Best Effort Service). In this arrangement, a data communications device routes video packets through a network differently than general data packets due to different link resource availability and resources being allocated differently based on the QoS class of the packets.
There are different types of QoS routing techniques. In one QoS routing technique (hereinafter called QoS class-prioritized routing), a data communications device internally prioritizes the processing of different QoS class packets in accordance with a pre-established QoS policy. For example, in accordance with one such QoS policy, a data communications device gives higher priority to video packets relative to general data packets. Accordingly, if the data communications device simultaneously receives a video packet and a general data packet (e.g., through multiple input ports), the QoS policy directs the device to process the video packet before the general data packet. As a result, in QoS class-prioritized routing, packet destinations (i.e., receiving host computers) generally perceive different responses, or Qualities of Service, for different QoS classes (e.g., faster video transmissions than general data transmissions).